The ratio of funds in gold ETFs to the gold price is at its highest level since the ETFs started to gain wider investor popularity in 2005.

Put another way, investor bullishness on the future movement of the gold price has never been higher. Despite the relative stagnancy of the gold price itself, investors continue to bet heavily on its future appreciation.

Especially unusual was the uptick seen in overall investment levels in May while the gold price fell. ETF demand tends to move in relative lockstep with price; as the gold price increases, so does ETF demand, and vice versa.

New data from the World Gold Council show retail and institutional investors in gold ETFs poured a net $771.3m into global funds in May, despite a pullback in the US, the largest market.

Global vaults now hold around 2,484 tonnes or a shade under 80m troy ounces after net inflows in May of 14.6t brought the year to date total tonnes acquired to 116.3.

US investors dumped nearly 30 tonnes in May, but the outflows were cancelled out by continued buying by Europeans and a surge in buying in Asia.